Acromegaly is a condition characterized by excess secretion of growth hormone due in almost all cases to a tumor of the anterior pituitary gland. Surgical removal of the pituitary tumor is the usual first form of treatment offered, but this is curative in only approximately 70% of patients. If surgery has been unsuccessful, as determined by persistent biochemical disease, with or without residual tumor, treatment options are either radiotherapy or medical treatment. Radiotherapy had been used widely in the past, but its use has declined due to the high risk of hypopituitarism with time and the fact that it can take years to take effect. Medical therapy at this time is restricted to two drugs: the dopamine agonist bromocriptine, and octreotide, an analog of somatostatin, the natural hypothalamic growth hormone inhibitor. Bromocriptine can be successful in patients with acromegaly, but at large doses and a thrice daily administration schedule is required. Octreotide is successful in 60-70% of patients with acromegaly in normalizing GH and IGF-I levels, but it is very expensive and requires injections three times a day. Both medications are frequently accompanied by side effects. Therefore, other medical approaches are needed. We propose to treat patients with active acromegaly with a new medication, B2036-PEG. B2036-PEG is a new medication which blocks growth hormone action at a cellular level. B2036-PEG is a recombinant protein with similarities to growth hormone, but with mutations which allow it to bind very tightly to the growth hormone receptor, but which prevent activation of the receptor. As a result, IGF-I, the principal protein produced normally after GH receptor activation is reduced with this medication. B2036-PEG is given once per day as a subcutaneous injection. All patients with acromegaly have high IGH-I levels which is responsible for the symptoms and development of complications related to acromegaly. All patients have growth hormone receptors so we expect that this drug should have an effect in nearly all patients unlike the medications which are currently available which are effective in only 20-60% of subjects